The present invention relates to a source for generating singly and/or multiply charged ions, of the type including a glow cathode, an intermediate electrode and an anode having passage openings and defining a gas discharge chamber in which electrons and/or auxiliary gas ions form the ions, the source further being provided with a magnetic yoke which produces a magnetic field along a common axis of symmetry of the intermediate electrode and the anode.
Ions beams with energies above about 30 keV are often used in physical research, such as, for example, for particle accelerators used for research into atomic and nuclear physics principles, or for examining radiation damage in connection with reactor construction, or for biomedical uses, and in the ion implantation art to produce semiconductor devices. The amount of equipment required to accelerate multiply charged ions is substantially less than for singly charged ions. The high frequency accelerators used in high energy physics even require ions with a quite specific minimum charge so that sources for highly charged ions are very important.
A source is known, which is called a duoplasmatron ion source described in UNILAC Project Reports Nos. 8 and 9, (1973), available by Gesellschaft of Schwerionenforschung m.b.H., Darmstadf, Fed. Rep. of Germany, in which the energy of the ionizing primary electrons is limited due to the characteristics of the discharge structure so that an upper limit is placed on the realizable number of ion charges for each element.